1. Field of the Invention
This invention relates to an adjustable air stream introducing device, more particularly to an adjustable air stream introducing device for reinforcement of a blowing power of a primary air stream flowing through a duct.
2. Description of the Related Art
A conventional tubular coupler for reinforcement of a blowing or cooling power of a primary or dry air stream flowing through a duct, generally has an inner surrounding wall which includes a proximate surrounding segment that surrounds and that is distant from an output port of the duct radially with an annular space therebetween for introducing the air stream. It is desirable to have a device for adjusting the amount of air stream introduced into the tubular coupler to suit the user""s requirements.
The object of the present invention is to provide an adjustable air stream introducing device for reinforcement of a blowing power of a primary air stream flowing through a duct.
According to this invention, the adjustable air stream introducing device includes a tubular coupler with an inner surrounding wall which surrounds an axis and which confines a conduit adapted to be disposed downstream of a duct. The inner surrounding wall includes proximate and distal surrounding segments relative to a surrounding end portion of the duct. The proximate surrounding segment is adapted to surround and to be disposed distant from the surrounding end portion in radial directions with an annular space therebetween. A surrounding seat member includes a first inner peripheral edge which surrounds the axis to engage the surrounding end portion, a first outer peripheral edge which engages the proximate surrounding segment, and a surrounding seat area which is interposed between and which is integrally formed with the first inner and outer peripheral edges. The surrounding seat member has a plurality of internal ports which are disposed in the surrounding seat area to communicate with the conduit and which are angularly displaced from one another about the axis. A surrounding sash member includes a second inner peripheral edge which surrounds the axis to be disposed adjacent to the surrounding end portion, a second outer peripheral edge which is disposed adjacent to the proximate surrounding segment, and a surrounding sash area which is interposed between and which is integrally formed with the second inner and outer peripheral edges. The surrounding sash member has a plurality of external ports which are disposed in the surrounding sash area and which are angularly displaced from one another about the axis. The surrounding sash member is disposed to overlie and to be turnable relative to the surrounding seat member about the axis between a fully open position, where the external ports fully coincide with the internal ports, respectively, and a partially open position, where the external ports partly overlap the internal ports, respectively. A motor-driven actuator member is disposed to initiate rotating movement of the surrounding sash member between the fully open position and the partially open position.